Pair of Helmholtz coils for generating a uniform magnetic field perpendicular to the axis of the Teltron D series tubes. Teltron Tube Holder D allows the coils to be configured in the Helmholtz geometry or to produce magnetic fields aligned vertically, or coaxial, with respect to the tube axis. The maximum field strength generated by the coils (~ 10 mT) is approximately 300 times weaker than that produced by an MRI machine (~ 3T), which are known to be safe for use by people with medical implants such as pacemakers.Specifications: